This invention relates to a wheel tire adapted to be filled with a gas under pressure. Such tires are widely used for vehicles and on the landing gear of aircraft.
Such tires have a tendency to radiate noise, especially at higher speeds. Such noise frequently amounts to a nuisance and is considered an acoustical pollution which the manufacturer wants to reduce. The noise radiation is caused primarily by body sound vibrations which in turn are caused by an uneven surface on which the tire rolls and by the segmented tire profile itself. These body sound vibrations cause a secondary air noise radiation. In addition to the air noise radiation, a rolling tire causes noise due to the so-called air pumping occurring at the contact area between the tire tread and the road or runway surface. However, the air pumping is of minor significance compared to the air noise radiation.
Prior art efforts to suppress tire noise have been directed primarily to the formation of the tire profile and to the selection of special rubber mixtures. For avoiding air pumping, the tire profile was made to form an open pattern for avoiding the trapping of air. It has also been suggested to use an uneven tire profile division around the tire circumference in order to eliminate troublesome resonance conditions. However, uneven tire profile divisions achieved only a relatively small, partial success. This applies as well to the use of damping rubber mixtures for making tires. The loss factor of such damping rubber mixtures for converting noise or sound energy into heat is limited. Further, it is difficult to match a damping rubber mixture in a damping sense to the relatively stiff carcass of the tire which forms part of the force flow. Thus, the results of prior art efforts to reduce tire noise radiation have not yet been entirely satisfactory.